Jadeite ABC Treatment System:

Type A jadeite means untreated.
Type B jadeite involves bleach or acid treatment.
Type C jadeite has been stained or dyed. 
Type B+C jadeite has been both impregnated and stained.

Basic Testing Tools for Jadeite Buyers:

1: Chelsea Colour Filter (Jadeite & Emerald)
In gemmology, it is used for identifying coloured stones. Jadeite(chromium, with iron) and Emerald(vanadium-free) emit a red fluorescence when illuminated by chelsea colour filter. (Not exactly, reference only)

2: 365nm UV Light (Jadite & Nephrite)
B+C Jade with chemical enhancement treatment will show fluorescence under 365nm UV light like the pictures below. However, the polish wax will also show tiny fluorescence under the 365nm UV light sometimes but it is not considered as enhancement treatment.(Not exactly, reference only)